The present invention relates to a vibration motor driving apparatus that generates haptic rhythms using a vibration motor. More particularly, the present invention relates to a vibration motor driving apparatus that it uses a serial interface without the existing PWM controller to generate various resonance frequencies in case of an event, use various types of vibration motors by controlling resonance frequency to operator vibration motor, improve the pulse capacity by precisely adjusting resonance frequencies, and control the operation and amplitude of vibration motor accurately and precisely. Therefore, it can be applied to all electronic devices that use vibration motors to generate various haptic rhythms, such as mobile devices.
Recently, haptic phones and electronic devices have been released to gain popularity among users. The haptic devices are equipped with haptic functions to generate various haptic rhythms for distinguish and maximize the effects of UI (User Interface) that simply used vibration, ring, or LED lights in case of certain events (pressing buttons or playing games).
The present invention relates to the operation and control of a vibration motor driving apparatus that operates the vibration motor for haptic functions. FIG. 1 illustrates a block diagram of a conventional vibration motor driving apparatus.
As shown in FIG. 1, a conventional vibration motor driving apparatus 200 receives PWM signals from the main processor 100, uses a fixed divider 210 and XOR (Exclusive Or Gate: 220) to divide the PWM frequencies entered, and amplifies them into reverse and non-reverse signals through an integrator using the capacitor inside an amplifier 240 to output the actual waveform to operate the vibration motor 300.
However, this type of vibration motor driving apparatus can only generate a fixed resonance frequency to operate AC-type vibration motors (LRA motor, etc) by processing the PWM signals through the fixed divider 210, XOR 220, and the integrator inside amplifier 240, and cannot use the vibration motors using various resonance frequencies.
In particular, PWM type requires the clock frequency of the main processor 100 to match the resonance frequency of the vibration motor 300, but it is difficult to equalize them as each type of vibration motor has different resonance frequencies.
Furthermore, the vibration motor designed to have a consistent resonance frequency may generate slightly different resonance frequency due to inconsistencies in the manufacture process. Thus, the improvement of the pulse capacity of the vibration motors has been limited as a precise adjustment of the resonance frequency considering the offset of each vibration motor has been impossible.
It is also difficult to provide the accurate and precise amplitude control to operate the AC motor (LRA motor) and DC motor (ERM motor) to convert PWM duties into the amplitude that decides the strength of pulse of vibration motor.
As the main processor 100 needs to output the PWM signals, the processor 100 is required to have PWM functions. The processors without the PWM signal output function cannot use this type of operator or require many additional peripheral circuits to operate the vibration motor driving apparatus.